If you have a hard time following all the Neandertal genomics findings from the last few years, and their implications, National Geographic has a really thorough piece up. It’s a good digest of all the news you can use. One thing I would like to add: from what I can tell the probability of the signals of admixture in non-Africans being genuinely Neandertal seem to be increasing as we progress. In other words, you should weight the “other side” (ancient population structure, where some African populations were closer to Neandertals before they left Africa) less than you did in 2010.

Of course one of the more inevitable aspects of the admixture story has been the humanization of Neandertals. I don’t know how I feel about this. Should our own affinity to Neandertals alter our view of their behavior or anatomy? Plenty of behaviorally anatomically modern humans were beastly after all.

National Geographic: Take any two unrelated humans today, Pääbo noted, and they’ll differ in millions of places in their genetic code. But the Neanderthal genome varies on average from that of H. sapiens in only about a hundred thousand positions. Pääbo and his colleagues are now trying to figure out the consequences of those differences.

My math indicates something got lost in translation, here.

Sandgroper

“Should our own affinity to Neandertals alter our view of their behavior or anatomy?” No, it should be irrelevant.

Maybe it’s just me, but I think it says something unpleasant about a person, when that person goes from having some condescending view of another lineage to ‘getting in touch with their inner …..’ (fill in the blank) when they discover to their surprise that they have some ancestry.

Scott

Meh…the debate over the humanness of Neandertals predates the genomic data. Sure, there were splitters who tried to classify them as a separte species, but no one should be suprised that the genomic data support admixture. To me, Neandertals were always human enough. I’m sure future work will just confirm this further.

The more interesting question is, how human was H. erectus? They were around longer. They also left Africa. They used tools. I’d love to see better genomic data from them.

jose

@2 And what does it say about a person who has that reaction? Please enlighten.

Sandgroper

#3 – And possibly controlled use of fire, at least sometimes, which seems to me more significant than tools. (Some other species use tools, but it seems only Homo do not fear fire.) (The surprising thing to me is why there is a lack of evidence of the controlled use of fire in Europe for such a long period during the Paleolithic.)

#4 – Something unpleasant (undifferentiated, meaning I can’t be fucked to try to psychoanalyse people, I just know I don’t like it).

Michael Watts

Eurologist: This is my _guess_ at what National Geographic means:

“Take any two unrelated humans …, and and they’ll differ in millions of places” — Most loci are not fixed; rather, the human population is characterized by a distribution of variants at that point.

“But the Neanderthal genome varies *on average* from H. sapiens in only about a hundred thousand positions” — At most of these non-fixed loci, the human population and the Neanderthal population are characterized by identical distributions.

So if we took an arbitrary human, and an arbitrary Neanderthal, there would be roughly 100k loci which we’d expect to differ based solely on the fact that one was human and one was Neanderthal. This would also let us make predictions about which variants would occur in which examinee.
But, there would be millions and millions of additional loci which would differ between the two, but not in any way _which was predicted by the species difference_ . Those loci would show differences because they were variant in humans, and similarly variant in Neanderthals. Differences in this category couldn’t be predicted to go one way or the other, since (by hypothesis) the human and the Neanderthal are equally likely to display any particular variant.

Chad

This thought just occurred to me. The idea of homo sapiens and neanderthals getting it on isn’t so shocking when you remember that there are 21st century men in this world who like to get it on with sheep or really anything else that strikes their fancy. Sex with a Neanderthal seems pretty normal by comparison.

https://plus.google.com/109962494182694679780/posts Razib Khan

#7, that was greg cochran’s response in the might aughts when ppl were aghast as the suggestion of human-neander mating. also, it isn’t 21st century. these behaviors were publicized by the kinsey report in 1950, unrepresentative though it was.

T

In a world of zedonks, ligers, and beefalo, I don’t see how people kept a straight face when saying the we didn’t hybridize. I really don’t think that we should make excuses for people who dismissed the possibility. I think that they were blinded by the agenda of political correctness, that is to say adherence to a very strict out-of-Africa orthodoxy. The biology has been there all along: closely related species can and will produce fertile offspring. We haven’t advanced in terms of that theory, but merely in terms of finding the evidence. People did propose hybridization, but no one took them seriously. Sure they had no real evidence, but neither did the side rejecting hybridization. In the absence of evidence people should have gone with the parsimonious explanation: that there was no particular mechanism to prevent hybridization, and thus hybridization happened.

gcochran

I’m not sure how much political correctness had to do with it. I think that paleontologists simply didn’t know much about mammalian hybridization. They hadn’t studied it in school, and they would have had to dig around in a library for hours to find out, which is too much to ask of anybody. Same for molecular geneticists. In addition, paleontologists confused morphological species with biological species, a mistake that no one who had seen a dachshund and a poodle getting it on at the 50-yard line during an Ohio State game would ever make.

The real importance of hybridization lies in the introgression of adaptive alleles, which takes only a smidgen of contact. That was implicit in early work by Haldane, and well-known to plant geneticists, but apparently all the well-known players in this argument were unaware of it.

Sandgroper

European male/East Asian Female combinations produce a higher % of birth difficulties than European/European and East Asian/East Asian. It’s not much of a stretch to imagine that Neanderthal/AMH pairs might given rise to birth difficulties. Plus it was not known whether any surviving hybrids would be fertile. Plus Pääbo’s earlier work on mTDNA suggested no introgression – of course we all (?) now know the fallacy in that thinking.

No political correctness required. It was not looking likely at the time. Now it’s looking more likely, but not yet fully conclusive.

gcochran

It was highly likely, if you thought hard about it. It takes a good deal longer than half a million years for mammalian sister populations to stop being interfertile: look at the record.

As for those that said that people just couldn’t have done anything that gross – well, that’s just stupid.

Scott

Is “hybridize” even the right word when talking about a sapiens vs neandertal cross? I mean there are at least a couple of million years between lions and tigers.

I agree with #12. Maybe I’m a letch, and I guess it depends on how different they really were culturally and in appearance, but I don’t blame either side for hitting that.

Yong

11 What about East Asian male/European female combinations? That happens sometimes too.

AG

@14

Just think about pelvic size of European females vs East Asian females. A simple deduction should help.

“also, it isn’t 21st century. these behaviors were publicized by the kinsey report in 1950, unrepresentative though it was.”

I´m not sure about what you mean, Razib, but I can assure you that these things are still very common in some places of the globe _ particularly when involving young men full of hormones and suitable animals.

Yong

15

It seemed to me like he was implying the difficulties are due to racial hybridization, as he’s talking about hybrids being thought to be not as fertile, and not because of physical limitations of or differences between Neanderthals and Sapiens. Besides, hip size is deceptive in terms of the size of the birth canal, from what I’ve read, which is why petite women are found no less “attractive” and just as fit for reproduction.

ackbark

15. It doesn’t suggest that at all since modern policies to do exactly that haven’t existed in any previous era.

Sandgroper

#17 – No, AG is right, I was talking about a higher % of birth difficulties due to pelvis/birth canal size relative to baby head size, and mentally trying to extrapolate that to Neanderthal/anatomically modern human. I’m making the implicit assumption that the male would be Neanderthal and the female AMH.

Separately, I mentioned that there was no evidence at the time that hybrids would be fertile. Even now, it looks possible that they might have been fertile only rarely. Or not – we have no real idea how often interbreeding events might have taken place.

I take Greg’s point about mammalian hybridisation, but birth difficulties in humans are not that rare, and both AMHs and Neanderthals are/were human.

I said nothing about grossness – this is not a sexual act with an animal of another genus that we’re talking about. The reference to sex with sheep is totally irrelevant in my view. We’re talking about sex between two humans, there’s no call to invoke bestiality.

Sandgroper

Yong – You can check the data – petiteness and attractiveness aside, data show that European male/East Asian female pairs have more birthing difficulties than other combinations because of the birth canal – baby size issue.

It’s not a reason for them to not do it, you understand. Birthing difficulties happen – it’s our (human) fault for developing big brains.

Yong

Interesting, I had no idea there was such a significant difference in baby size/head size depending on race. I always thought of East Asians as having comparable head sizes, or even slightly larger, to other races as adults. I wonder also to what degree this comes down to personal mate selection. Even today, are there such significant differences in size between Asians and others? With development and improved nutrition, the differences on average have leveled out. Maybe this research was done with really small Asian women and not normal to larger size Asian women? I’m an Asian male in my 30s and I’m 5’9″. I’ve noticed that most younger Asians are as big or usually bigger than me, females included.

If they took those tests for birthing difficulties again in say, 5-10 years, would the difficulties still exist? I doubt it. I don’t think a half-white, half-Asian baby is so much bigger than a 100% Asian baby such that it would account for difficulty with birth for an Asian woman.

Do you have links to any research? I saw something from 2008 about a California study but did not find much info on the subject.

Sandgroper

Most East Asian females younger than you are taller than 5’9″?

Would you like to put some money on that?

Yong

No, I wouldn’t put money on it. It’s purely an anecdote. I ride the subway almost every day and I’ve just observed a lot of tall younger Asians, much to my chagrin. I feel like a runt compared to them, even the female ones. Maybe I’m just noticing the unusual and not the more ordinary. Another anecdote: my sister has had two children with a white father with no labor problems. The second one she said was easier than the first.

I’d just like to see more data specific to this circumstance, and that takes into account real measurements of pelvis, height of partners, etc. The hard evidence seems lacking.

https://plus.google.com/109962494182694679780/posts Razib Khan

#23, don’t be stupid. the median height for dutch women isn’t even 5’9 last i checked.

Sandgroper

Let me give you a hint: the tallest women in the world live in the Dinaric Alps. The mean height of young adult females there is 5’7.5″ (measured, not self-reported). The mean height of young women in China is 5’2″, Japan 5’2″, South Korea 5’3.5″, North Korean defectors 5.1 – the latter are the ones who are showing nutiritional depression of height. The mean height of young American white women is 5’5″. It is clear you will be unable to produce data to support the notion that most young Asian women living in America have a mean height in excess of 5’9″, unless you restrict your sample to Beijing and Shanghai super-models or the national volleyball team.

What matters here is weight/head size at birth. That Californian study was taken from case histories over the period 2000 to 2005. Do you really think nutrition has improved that much for Asians living in California in the past 7 years? I would be surprised if it had changed at all during that period. Post 2008 I guess it’s possible it even got worse.

The study reported that Asian babies had lower median birthweights than European babies. It also reported a much higher rate of Caesarian deliveries for Asian mothers with European husbands than for European mothers with either European or East Asian fathers. They attribute this to possibly smaller pelvis size in Asian than in European women.

White mother/Asian father had the lowest rate of Caesarian births of 23%, compared to 33.2% for white father/Asian mother. If that’s not an issue of the head size versus the pelvis/birth canal size, which is it caused by?

Have you ever watched a baby being born up close? It’s a tight fit and a very painful process, and the baby’s head has to change shape to get through the birth canal. It doesn’t take much of a size difference to create a major difficulty.

Assuming Neanderthal babies had bigger heads than AMH babies, which seems like a reasonable assumption, then the birth could be really difficult, and there were no surgeons around to perform Caesarian sections back then, so far as I know . It doesn’t necessarily mean it was always impossible – there’s a natural variation in head size in babies. But it could suggest that successful Nanderthal/amh births were not that common. The child would then need to grow up among amhs, becuase the alternative was extinction.

This all suggests that successful hybrids who went on to breed themselves successfully with amhs were a rarity.

Case closed, I’d say.

Sandgroper

Mean height of young Dutch females is 5’6″.

Yong

The study you linked to says the results “suggest” smaller pelvises but no actual pelvic measurements of the people in the study are given. What were their heights? Could it be many couples consisting of short Asian women and taller husbands? Shorter women on average have more c-sections. How many of each couple? I’d say Asian female and white male couples far outnumber the reverse. Can the data be compared then and given as much weight as if there were an equal number of each coupling? According to this article http://www.childbirthconnection.org/article.asp?ck=10456, the national average for c-sections was 32.8% in 2010. That’s not even 1% less than the rate among Asian female white male couples.

Also, what were their ethnicities? “Asian” covers everything from India to Tibet to Southeast Asia all the way down to Indonesia and the Phillipines. Sometimes “Asian” even includes Middle Easterners. There must be pelvic variation among all the Asian ethnicities.

Say you are correct though, and it’s a pelvis issue. There could just as well have been homo sapiens males mating with neanderthal females.

https://plus.google.com/109962494182694679780/posts Razib Khan

#27, i’m skeptical of sandgropper’s model. but please engage it directly and not speciously, or you’re wasting everyone’s time, including yours. the median height of asian females in the subway or where you interact with them is NOT 1 standard deviation above that of dutch women. if you perceive this, go check your perceptual abilities. something is lacking. sandgropper is not talking about middle eastern when he says “asian.” you know that, i know that. for the purposes of this weblog he’s talking about east and southeast asia. south asians “don’t count” in a genetic sense.

try and make this discussion useful, instead of randomly firing weird and confusing assertions.

Bill

Weaver and Hublin (2009) have suggested that Neandertal females gave birth without rotation of the newborn on the way out. Could differences in pelvic shape between Neandertals and “moderns” have presented correlated obstetrical challenges to mothers of such hybrids?

Isabel

“But it could suggest that successful Nanderthal/amh births were not that common”

Wait what about Hss males and Hsn females? They may have had easier births than they usually would have.

Sandgroper

#29 The California data suggest that European females/Asian males have an easier time of it, so if my ‘model’ had anything to recommend it, your question would instantly torpedo it. I’ve always pictured hybridisation events as Hsn males + Hss females, on the thinking that Hsn females should have been better able to defend themselves if ambushed.

It’s moot in any case – some fertile hybrids apparently did survive, unless what we’re seeing is ancient population structure in SSA, and the evidence seems to be moving away from that (and considering that hybridisation with Denisovans evidently also did occur). I was just trying to explain why past doubts about Hsn/Hss hybridisation were not necessarily a result of political correctness or the ‘grossness’ factor. If the ‘grossness’ factor had any relevance, a substantial subset of people in America, Australia, UK and Mexico would no longer be reproducing, which is obviously not the case.

Of course there’s always the ‘hello sailor’ factor.

Isabel

“hello sailor”? What does that mean? Are you suggesting the Hsn women were prostitutes? lol.

Maybe there was a hybrid zone, where people could find others who were not too different from them selves

Yong

It’s true my arguments so far have been scattered all over the place. Sorry for that.

I still haven’t seen any totally convincing evidence for a significant difference in pelvis size by race, such that it would lead to more c-sections. If 100 couples of comparably sized Asian females and white males – say both partners are around 5’6″ – had children, would the c-section rate be above average? I doubt it. But that’s just a gut feeling. And I think when it comes to possible rape being involved, a homo sapien male would have managed even against a neanderthal. But who knows, they might have just been into it. There were probably few to no social constraints back then about that kind of thing.

Chad

Yong, look at their feet. Heels add height.

Sandgroper

#32 – “You give me woolly rhinocerous liver, I love you long time.” It happens. Maybe not as much as some people might like to imagine, but it happens. A lot of early hybrid births in Australia after European invasion (you can see I’m getting in touch with my ‘inner Abo’ here) resulted from Aboriginal women trading sexual favours for alcohol and foodstuffs. It’s one way I could envision Hss male/Hsn female relations happening. I hadn’t thought of it before, but it seems a possibility.

Hybrid zones do still happen too, among a lot of first generation hybrids – restaurants, bars, chat-rooms and stuff. There are schools here where about a 2/3 majority (not an exaggeration) of the students are first generation hybrids.

Yong

34. I do look to see if they’re wearing heels or boots sometimes, to make myself feel better. “This girl is not really as tall or taller than me, she’s just wearing boots.” But then I feel like I should still be taller.

35. “You give me woolly rhinocerous liver, I love you long time.” LOL

The trend definitely seems to be going in the direction of “hybrids” all over the world. Certain places, like Hawaii and other parts of America, Brazil, Macau have been like this for a while. These days I see more and more mixed couples and mixed children. As an aside, I feel kinda weird using the word “hybrid” like we’re talking about cross-pollinating orchids, or breeding dogs or something. But then again, we’re animals too. It’s not that weird. I don’t like to deify humans.

Yong

Did you guys notice this head size/birth canal topic made its way to Dienekes’ blog?

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Gene Expression

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com